Electric power cable



Dec. 31, 1940. c, MEYER ELECTRIC POWER CABLE Filed Feb. 12, 1938 INVENTOR ATTORNEYS Patented Dec. 31, 1940 UNITED STATES PATENT OFFICE amc'rmc rowan ennui Jersey Application February 12, 1938, Serial No. 190,232

This invention relates to accumulators particularly adapted for use in electric cable systems wherein the insulated conductors are drawn into a pipe line filled with oil which is maintained 5 under a pressure sufllciently high to increase its dielectric strength, say, for example, 200 pounds.

One of the objects of my invention is the provision of an'accumulator wherein gas is used as the pressure medium, a construction being-prom vided whereby loss of the gas due to leakage past stuiling boxes is eliminated. In practice bottled gas is employed as the pressure medium, and inasmuch as it is comparatively expensive loss through leakage materially increases the cost of '15 maintenance of the system.

In the accompanying drawing the single figure is a sectional elevational view of one embodiment of my invention.

Referring to the drawing in detail, my improved accumulator comprises upper cylinder section 2 and lower cylinder section 4 united by suitable coupling 6. Within this cylinder is a cylindrical member 8 divided about midway of its length by a transverse wall or partition i0 into two hollow pistons, an upper piston l2 and lower piston I 4.

l8 designates a cable system which is operated under pressure. It may be, for example, a cable system of the type wherein insulated conductors it are loosely enclosed in a pipe line 20 filled with oil under pressure. The purpose of the accumulator, of course, is to allow for expansion of the oil on heating of the cable when the same is under load and to force the oil back into the system as the oil cools down.

The lower piston i4 is in constant communication with the cable through the line 22, for example.

The upper piston i2 is filled with oil and is in communication through pipe 24 with a reservoir 28, which is partially filled with ofl, as shown at 28. The space 30 above the oil 28 is filled with gas under pressure from a supply tank or bottle 32..

It will be appreciated, of course, that the pistons i2 and II will rise in the cylinders 2 and I under volumetric changes in the oil in the cable i6, thereby to maintain a substantially constant pressure on the cable. The size of the gas reservoir and piston is determined by the pressure range and stroke desired.

As above pointed out, trouble has been experienced in the past with loss of gas, but in my improved construction it will be appreciated this trouble has been eliminated inasmuch as the parts are so designed that in the lowest position of the pistons I2 and I! there is always oil in the reservoir 26, thereby preventing escape of gas past the stufilng boxes 34 of the accumulator.

It will be appreciated the pressure gas is always out of contact with the cable oil.

It will be appreciated that changes may be made in the details of construction and arrangement of parts hereinabove described and illustrated within the purview of my invention.

What I claim is:

A closed electric power cable system comprising in combination a fluid fllled cable, a cylinder in constant communication with said cable, a second cylinder spaced from but alined with the first mentioned cylinder, a hollow piston common to said cylinders, an imperiorate barrier in said piston intermediate its ends, the fluid of the cable contacting the lower face of the barrier to effect outward movement or the piston as the fluid of the cable expands due to cable operation, a liquid in the said second cylinder and contacting the upper face of said barrier, and a gas under pressure upon the surface of said liquid for resisting outward movement of the piston as the cable fluid expands and for moving the piston inwardly as the cable fluid contracts.

, FRED C. MEYER. 

